It has led to calls for radical action to address the problems with our jammed-up road network.

Today’s report examines traffic flow in cities across the UK.

It found the total cost of congestion to Belfast alone in 2017 was £140m, with Londonderry second at £51m.

Coleraine came third, with traffic jams costing £38m.

The A1 was Northern Ireland's most congested road with the A23 in Co Down and B38 in Co Antrim coming second and third respectively.

Dr Graham Cookson, chief economist with INRIX, said the costs were shocking, and called for action to free up our roads.

“Combined with the rising price of motoring, the cost of congestion is astonishing – it takes billions out of the economy and impacts businesses and individuals alike,” he said.

“With the Office of National Statistics showing more cars on the road than ever before, we need to consider innovative new approaches to solving the issue.”

The INRIX report took into consideration the value of fuel and time wasted by congestion.

It also looked at indirect costs relating to freighting and business fees from company vehicles idling in traffic that are passed on to household bills through higher prices.

Economist Dr Esmond Birnie, of the Ulster University’s economic policy centre, said: “This is an interesting report based on a mass of international data relating to traffic congestion.

“It confirms everyday experience — congestion is a considerable issue here in Northern Ireland as it is elsewhere.

“There may be room to debate whether the true cost is just as high as this report argues — £1bn-plus — but, for sure, the cost is considerable and this study does not add in an allowance for the environmental impact of congestion.”

Dr Birnie said a range of measures could be taken to cut congestion in Northern Ireland — including more people working from home, variable working times, congestion charges and further infrastructure investment.

He added: “The report implies, as a percentage of the size of the economy, congestion is more costly in Northern Ireland than the UK as a whole.

“It is about 2.4% of GDP in NI, but about 2% of GDP for UK on average.”

Motoring organisation the AA said a range of factors had combined to leave more cars on the road.

A separate study by the organisation recently said that of those drivers commuting more than 10 miles to work, 17% were for reasons beyond their control.

Some 9% of drivers surveyed took on the commute due to their workplace being relocated, 6% because they were made redundant and their next job was further away and 2% because they had to move further out of a city to find affordable housing.

An AA spokesman said: “This report is bad news, not only for the economy, but for drivers who have to go through this daily grind of working their way through traffic to get to work.

“There is an image that is portrayed that drivers are somehow to blame for congestion and that they have an alternative. So we wanted to show what percentage of people were doing the long daily commute not through choice.”

Roads expert Wesley Johnston said it would be difficult to cut congestion on Northern Ireland’s roads.

He referred to the ongoing work around Belfast Rapid Transit, which will create a new public transport system for the city.

“The Department for Infrastructure (DfI) is focusing on upgrading the inter-urban roads,” he said.

“There is not an awful lot happening in terms of easing congestion through road building in Belfast. Belfast Rapid Transit is the main scheme that is being put in place.

“At the minute the roads, particularly in Belfast, are congested as there is no more space and the only way to create more space is to demolish — which can’t really happen in the city centre.”

Mr Johnston said that efforts to encourage people into other forms of transport were not intended to reduce congestion.

He said: “What it is designed to do is get more people into the same road space. Belfast Rapid Transit probably won’t reduce congestion for car drivers — in the short-term it could make it worse.”